The present invention relates to apparatus for location and treatment using ultrasound. It notably applies to focused ultrasound treatment of myomas or other types of tumor having a pedicle. It also applies to the locating and treatment of blood vessels.
Myomas are accumulations of muscular tissue attached to the uterus, or, in; other words, are particular fibromas. Three types, depending on their location, are distinguished:
subserous, i.e. external to the uterine cavity;
in the uterine wall,
inside the uterine cavity.
Subserous myomas are of little concern, except when they are very large. Myomas in the uterine wall present problems of bleeding. Myomas inside the uterine wall become reduced after the menopause except where the patient receives hormone replacement treatment. They require treatment if they prevent conception.
Myoma ablation involves the use of the following surgical techniques:
myomectomy by laparotomy;
myomectomy by coelioscopy;
hysterotomy by hysteroscopy.
Myomectomy by laparotomy or coelioscopy has the disadvantage of the cicatrix on the uterine wall remaining fragile. Intervention by hysteroscopy presents the problem of limiting operation time due to bleeding and glycocoll resorption. This procedure consequently only applies to small myomas, i.e. from 3 to 4 mm. This procedure further requires great operational skill, and can be dangerous.
It has further been proposed, experimentally, to treat myomas by embolization; the essential problem with this treatment is that it is very painful during expulsion of the necrosed mass.
Myomas are visible by abdominal or transvaginal echography. With transvaginal echography, the probe is placed on the axis of the vagina, perpendicular to the major axis of the uterus. With abdominal echography, the probe is placed on the patient""s abdomen.
The technique of hystero-echography is advantageously employed for locating the myoma. A small amount of serum is instilled for separating the two loops of the uterus, typically using a 2 mm catheter introduced by vaginal route. This technique is not painful in view of the very small pressure needed to detach the loops of the uterus.
B-mode echography can be used to identify the fibroma, its anatomical relations and the vascularization around the fibroma which is irrigated at its periphery from a pedicle.
In a quite separate therapeutic area, ultrasound treatment and locating probes have been proposed for benign prostate hyperplasia treatment. One can notably refer to WO-A-89 07909 (Fry), or WO-A-95 02994, in the name of the applicant. These probes are suitable for prostate treatment, but do not have the geometrical and ultrasound characteristics allowing myoma treatment. For ultrasound location, these probes comprise echographic transducers used in A- or B-mode. WO-A-93 17646 discloses ultrasound prostate treatment apparatus; the apparatus has an external therapy transducer. For imaging, it is proposed, firstly, to use a rectal probe and, secondly, to provide an imaging probe at the center of the transducer. Again, there is nothing in this document suggesting treatment of myomas or tumors having a pedicle.
Further, tests have been carried out for attempting to coagulate blood vessels by focused ultrasound: see for example Delon-Martin C., Vogt C., Chignier E., Guers C., Chapelon JY., Cathignol D., xe2x80x9cVenous thrombosis generation by means of High Intensity Focused Ultrasound.xe2x80x9d Ultrasound Med. and Biol.; 21; 113-119; 1995. However, that article does not provide for secondary necrosis of tissue. The authors employ Doppler echography for monitoring blood flow before and after exposure, i.e. for evaluating the effects of ultrasound application. They do however not use Doppler echography for locating the vessels to be treated.
The article by Schultz-Haak xe2x80x9cUltrasonic treatment of varicose veinsxe2x80x9d in Journal of Vascular Diseases Vol. 40, No. 2, Feb. 129-137 provides for focused ultrasound treatment of certain uterine afflictions but does not disclose the precise apparatus for this. Finally, Moussatov AG, Baker AC, Duck FA envisaged certain gynaecological treatment using focused ultrasound in their article xe2x80x9cA possible approach to the treatment of polycystic ovarian syndrome using focused ultrasoundxe2x80x9d Ultrasonics 36, 893-900 1998. There is no mention of myomas in this article and there is no description of apparatus needed for destroying or locating them.
U.S. Pat. No. 5,880,302 discloses apparatus for hemostatis treatment. This apparatus is designed to stop internal post-traumatic bleeding using focused ultrasound. The apparatus takes the form of a probe designed for introduction into a cavity, such as the vagina, oesophagus, etc; it has a transducer element which is associated with an imaging probe; the latter uses Doppler imaging for producing an image of the region to be treated, and notably of blood flow. Doppler imaging can also be used for providing information about the regions treated. There is nothing in that document suggesting treatment of myomas or tumors by pedicle necrosis. Finally, this document does not indicate how the probe can be positioned using Doppler imaging.
European patent application 0,734,742 discloses therapy apparatus using external ultrasound, consisting of an electronically-focused therapy transducer, with an imaging probe. In one embodiment, the use of two-dimensional Doppler imaging is proposed. This document also does not suggest treatment of myomas or tumors having a pedicle. There is no explanation regarding probe positioning.
There is consequently a need for myoma treatment apparatus, allowing their destruction, which is:
ambulatory (ie without hospitalisation)
preferably, without anaesthetic
without blood loss
easy to use;
accompanied by a minimum of secondary effects or complications;
and which allows ready and effective location of regions to be treated.
The invention allows myoma treatment, with all these advantages. It applies more particularly to the treatment of myomas inside the uterine cavity as well as myomas situated in the uterine wall or on the other side thereof with respect to the probe, to the extent they can be reached by the probe of the invention, determined by the focal length of the ultrasound transducer employed.
The invention also provides simplified location and treatment of blood vessels.
More precisely, the invention provides apparatus for location and treatment using ultrasound, comprising at least one therapy transducer and at least one imaging transducer, and a pulse generator exciting said therapy transducer, and exciting said imaging transducer for Doppler echography. It is particularly advantageous for the imaging transducer to be in a fixed position at the center of the therapy transducer.
Doppler echography can be used for locating the region to be treated, for positioning the therapy transducer, before or during therapy; it also can be used to indicate the end of treatment.
In one preferred embodiment, the pulse generator excites the imaging transducer for pulsed Doppler echography.
In one embodiment of the apparatus, the therapy transducer is carried on a probe, preferably a vaginal probe.
In the case of a vaginal probe, the therapy transducer is arranged at an end of the probe, for allowing uterine tissue treatment.
Preferably, the therapy transducer has a focal length suitable for uterine myoma treatment when the probe is introduced into the patient""s vagina.
In a further embodiment of the apparatus, the imaging transducer is arranged on said probe.
In this case, the imaging transducer and therapy transducer can be one and the same unit.
In a further embodiment, the apparatus has a second probe, preferably external, on which said imaging transducer is provided.
In the latter case, the apparatus can comprise means for measuring the relative position of the probe carrying said therapy transducer and said probe carrying the imaging transducer.
The invention also provides a method for positioning a therapy transducer in apparatus according to one of claims 1 to 10 for subsequent treatment of a tumor having a pedicle or a myoma, comprising a step of maximizing the Doppler signal from the imaging transducer.